[humbleferret]

I was curious so looked at a few power wheelchairs...It's wild how expensive they are, especially considering the advancements in electric mobility tech elsewhere. You'd think they'd share some components with e-scooters, e-bikes, or even electric cars – motors, batteries, controllers.

Are the powertrains and control systems in power wheelchairs really that specialised? Or is it another case of the medical device markup and regulatory hurdles driving up costs?

[amiga]

I'm a guy who has disassembled and reverse engineered a standard Jazzy power chair, and what I noticed was the attention to detail regarding failures. The chair is thoroughly designed to shut down at the slightest bit of trouble. There's some redundancy in things like the controller, where it used redundant hall effect sensors that were identical to the others, but ran in an inverted power profile, to detect any weirdness in the sensor outputs.

I ended up adding a long range remote control to it. A remote control power chair is fun to drive around. People do get a little concerned when they see a chair rolling around without a driver

[orlehuxwell]

My mum recently had a curbside crash while she was riding an e-bike. This resulted in her breaking bones in both her hands, which resulted in a surgery in her left hand and various problems (tcl fracture related) with her right hand.

This makes me actually appreciate reliability in e-vehicles motor cutoffs etc. I keep thinking if this could have been avoided with a better quality e-bike or if actually it would be even worst with a cheaper one.

Which makes one think, how often a wheelchair with cheap e-scooter parts would crash people into staris, cars etc

[TeMPOraL]

I know public use devices have their own problems with reliability, but I did almost cause a traffic accident a couple times over the years. Every time, the scooter's accelerator lever got "sticky" due to repetitive (mis)use, and would sometimes not go all the way to 0 when released. Stuck at ~10%, the scooter would brake normally and remain at halt under my weight, but the moment I stepped off it, it would suddenly launch itself at the cross traffic.

It's these little things that get you. The scooters all have some kind of debounce logic, disabling the accelerator until you're moving sufficiently fast - but the logic doesn't kick in when you stop without releasing the lever. A little bit of redundancy would've helped here.

[_flux]

A friend has an e-unicycle (I think the category devices has some other name as well..) and he wanted to try out how it behaves in a track.

He sort of knew, but didn't expect it, that when the roll of the device exceeds a certain threshold, the device will shutdown. Even if you're on a curve going with some speed. Broke his wrist. Since then he's also wearing wrist protectors that keep the hand straight.

Actually it was a bit unexpected that it would have known to do that; it must have used its complete IMU data to even know it was rolled, as plain accelerometer would have been pointing "down" as usual.

[leoedin]

I'm an embedded software engineer with past experience developing robotics and motor control drivers.

Those e-unicycles terrify me. No way I'd trust my life to one. Once you're at speed, every failure mode results in instant passenger ejection. I see people flying through traffic on those things - they're just one sensor glitch or integer overflow away from serious injury.

[snatchpiesinger]

> Actually it was a bit unexpected that it would have known to do that; it must have used its complete IMU data to even know it was rolled, as plain accelerometer would have been pointing "down" as usual.

That actually feels like overengineering based on well-intentioned, but wrong specs. You probably want to just use sideways acceleration for "falling over" detection, instead of roll.

[tim333]

The safety with ebikes does vary a bit although I'm not sure it's down to price. My one is quite a cheap one but has quite a lot of safety features - will only go if you pedal it, motor cut if you touch the breaks, 14 mph speed limiter etc. But I guess you can come off any two wheeled vehicle.

[crooked-v]

> People do get a little concerned when they see a chair rolling around without a driver

Add a hat and a scarf on a wire and you've got a Halloween prop.

[lynx23]

Assistive technology costs are high because consumers barely have an alternative. I am blind. In Europe, a 40-cell braille display starts a 6k. 6k, just for a monitor which displays 40 characters. Prices are largely unchanged since 20 years. Technological advancements are irrelevant. Resellers will squeeze the cow, thats plain capitalism man.

[pbasista]

If that is the case, then there seems to be a place in the market for someone else who can sell these devices for cheaper.

However, as you have pointed out, since it is also a market where people have few choices, there is no incentive for any new player to significantly lower the prices. Even if they easily could. Because they know that they will get the customers anyway.

That seems to be the root cause of the excessive price problem. An existing oligopoly of rent-seeking companies. Or a cartel, if you like.

I think that one of the ways to disturb this market and bring the prices down is for some honest company to join it and price their products fairly.

Once there is one such company, I assume that everyone else will lower their prices as well. Because otherwise they will run out of business.

[bluGill]

The problem is if you spend 100 million dollars to make one (which is about 30 engineers, 50 testers, and 20 other for a year) and sell 10,000 units (remember there is competition who will get come sales) you need $1000 each just to pay engineering costs. Lack of scale is what makes many products expensive.

[zestyping]

If you don't mind educating a curious person — why are Braille displays still worth making when text-to-speech is free, everywhere, and communicates information much more quickly than Braille? I can understand that there might be special situations where you really need a device to be silent, but it's hard for me to see how the cost-benefit tradeoff would weigh in favour of a Braille display except in the rarest of circumstances.

[mistercheph]

Just from googling -- an orbit reader 40-cell appears to cost $1,700 USD, is there a reason this doesn't actually solve the same problem as the 6,000 euro display, or are these not available in your market for that cost? Sorry if my question is off the mark, I don't know a lot about this and your comment piqued my curiosity.

[lynx23]

Orbit reader is the most low-quality device you can find on the market. This is like suggesting a bicycle to someone complaining about car prices.

[krisoft]

I’m sure the commenter meant well. You said “In Europe, a 40-cell braille display starts a 6k.” Which to me means that the most low quality, cheapest device starts at 6k.

Now i learn from you that that low quality device is so bad that you consider it a separate product class in itself. Can you tell us more what does it lack? In other words what features are you looking for when you are looking for a 40-cell brail display? (What is the minimum quality for it to be a “car” in your analogy?)

[K0balt]

This is a fascinating potential wedge for an open-source initiative. Could you please elaborate as to what makes a device highly usable and of good quality, vs cheap and unpleasant to use?

I’ve long thought that open source would make a lot of sense for assistive devices, and that it has the potential to change incentives within the cartel of assistive device manufacturing.

[ebalit]

There was a HackadayPrize 2023 competitor that worked on this [0]. He had to rethink the way those devices are built to bring the cost down.

That would be interesting to know if his solution could match the 4k$ in term of usability or if there is some issue like refreshing rate that make the piezo based system necessary for a good user experience.

[0] https://www.youtube.com/watch?v=BXi1tG78AW4

[K0balt]

That looks like a great project. I share your curiousity regarding the user experience of this vs the piezo units. Looking at it, it should be in the 50-100mS range for refresh times, maybe that is too slow? It seems like it would be plenty fast? I wonder if there are other haptic factors with the piezo, like vibration?

[mistercheph]

This is specifically like someone that has never seen or used a car or bicycle asking about why a bicycle wouldn't work for someone complaining about car prices, which I think is a pretty reasonable question!

[Cthulhu_]

I suspect a major difference is that those e-scooters, bikes, cars, etc are produced and sold by the millions, whereas wheelchairs are small volume by comparison. Another commenter mentioned the legal requirements, which complicates things.

That said, a quick google says there's 65-132 million wheelchair users worldwide so it's not a small market either.

[nothercastle]

Most of them are probably in countries where 1000 is a years wages.

[space_oddity]

...but the production and distribution of wheelchairs

[space_oddity]

I think a significant portion of the cost is related to the "medical device" label.

[tim333]

It's impressive and a little sad how cheap you can get them second hand.